Coupling between a centrifugal fan and the suction inlet thereof

ABSTRACT

The invention relates to a coupling between a centrifugal fan and the suction inlet thereof, comprising a suction inlet ( 1 ) defining an opening ( 2 ) for the passage of a flow of fluid under suction and a rotatably mounted centrifugal suctioning fan ( 3 ). A closure coupling is formed around the opening ( 2 ), between said centrifugal fan ( 3 ) and the suction inlet ( 1 ), by means of fitting together flanges ( 7 ) of the centrifugal fan ( 3 ) and flanges ( 8 ) of the suction inlet ( 1 ), which flanges define therebetween a labyrinthine passage that obstructs the ingress of an air disturbing flow through the coupling.

FIELD OF THE ART

The present invention relates to driving gaseous fluids for applicationsof any type, proposing a coupling between a centrifugal fan and asuction inlet with a closure “sealing” in said coupling conferringadvantageous features with respect to the current state of the art.

STATE OF THE ART

A type of apparatus commonly used for driving gaseous fluids indomestic, industrial or commercial applications are those formed by acentrifugal fan with backward-curved blades connected to a suctioninlet.

In said apparatus, the centrifugal fan defines a peripheral outlet,forming a coupling with an axial suction inlet, such that when thecentrifugal fan rotates, the blades thereof suction the gaseous fluid tobe driven through the suction inlet, expelling it through the peripheraloutlet.

In the functional arrangement of said apparatus, the suction inlet isfixed and the centrifugal fan is rotary, such that between said suctioninlet and the centrifugal fan a coupling which allows rotation of thecentrifugal fan must be formed; said coupling must, however, have playto prevent friction.

That play of the coupling between the centrifugal fan and the fixedsuction inlet causes the ingress of a flow of disturbing fluid throughsaid coupling because the action of the centrifugal fan inside theassembly causes negative pressure, which results in disturbance of themain suction flow, causing a distortion thereof, while at the same timeproducing more noise in the apparatus due to turbulences of the fluidcirculating therethrough.

The solution conventionally adopted for reducing those problems is tominimize the play of the coupling between the centrifugal fan and thesuction inlet, but this has a limitation due to variations in diametersand roundness and concentricity defects between parts, so the playcannot be less than a specific value.

OBJECT OF THE INVENTION

The purpose of the invention is to reduce the flow of disturbing fluidin the mentioned apparatus, defining to that end the coupling betweenthe centrifugal fan and the suction inlet in the form of a labyrinth,such that it is harder for the flow of disturbing fluid to pass throughthe coupling, significantly reducing the flow thereof.

To that end, said coupling between the centrifugal fan and the suctioninlet is defined by fitting together concentric flanges of both parts,play being generated between said concentric flanges forming thecoupling, preventing friction therebetween, but the fitting arrangementforms a path between flanges that obstructs the passage of the flow ofdisturbing fluid.

Loss of the suction effect produced by the action of the centrifugal fanin relation to the suction inlet is therefore reduced, as thecentrifugal fan is not affected by the braking effect in relation to thesuction inlet, such that actuation of the rotational operation of saidcentrifugal fan is used more effectively for the suction effect that issought through the suction inlet, the functional performance of saidsuction therefore being greater.

In that sense, the coupling between the centrifugal fan and the suctioninlet can define two or more concentric flanges of each of the partsbeing fitted together, whereby a labyrinthine path that obstructs thepassage of disturbing flow through the coupling to a greater extent isformed, said obstruction of passage of the disturbing flow increasingthe greater the number of concentric flanges forming the fitting of thecoupling.

As a result, said coupling object of the invention has very advantageousfeatures for the suction performance of the apparatus of application,this coupling acquiring its own identity and preferred character withrespect to conventional solutions in apparatus of the same type.

DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a perspective view of an assembly of a centrifugal fan anda suction inlet that are coupled according to the invention, thecentrifugal fan and suction inlet being depicted separated, in aposition facing one another.

FIG. 2 shows a perspective view of the assembly of the preceding figurecoupled to one another with a section that allows seeing the couplingbetween the centrifugal fan and suction inlet.

FIG. 3 is an enlarged partial detail of an assembly of a centrifugal fanand suction inlet connected to one another by means of a conventionalcoupling, depicting the main flow of fluid entering through the suctioninlet and the disturbing flow entering through the coupling between thecentrifugal fan and the suction inlet.

FIGS. 4 to 9 show different embodiments of the coupling between acentrifugal fan and a suction inlet according to the invention, fittingtogether concentric flanges that are axially oriented in the directionof suction.

FIGS. 10 and 11 show other embodiments of the coupling between acentrifugal fan and a suction inlet according to the invention, fittingtogether flanges that are radially oriented with respect to thedirection of suction.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a coupling between a suction inlet (1)defining an opening (2) and a centrifugal fan (3) defining peripheralopenings (4), such that in the functional arrangement, the suction inlet(1) is fixed, the centrifugal fan (3) being rotatably mounted withrespect to said suction inlet (1), such that rotation of the centrifugalfan (3) causes suction of a flow of fluid (A) through the opening (2) ofthe suction inlet (1), to expel it through the peripheral openings (4).

To favor that suction of the flow of fluid (A) through the opening (2),a coupling is formed around the mentioned opening (2) between thecentrifugal fan (3) and the suction inlet (1) by means of respectiveconcentric flanges (5 and 6) of both parts, said coupling having thefunction of defining a closure to prevent the ingress of disturbing flow(B) therethrough, since said disturbing flow (B) causes turbulence (C)in the interior which produces loss of the effect of the sought actionof suctioning the flow of fluid (A) through the opening (2) of thesuction inlet (1).

Nevertheless, the centrifugal fan (3) must have freedom of rotation forits function, so there must be play preventing friction between theconcentric flanges (5 and 6) forming the coupling around the centralopening (2) between said centrifugal fan (3) and the suction inlet (1),which results in a passage between said flanges (5 and 6) of thecoupling through which ingress of disturbing flow (B) causing turbulence(C) in the interior occurs, as seen in FIG. 3.

To reduce that ingress of disturbing flow (B), the coupling around theopening (2) is formed by fitting together flanges (7) of the centrifugalfan (3) and flanges (8) of the suction inlet (1), as depicted in FIG. 2,whereby there is a labyrinthine passage between said flanges (7 and 8)that obstructs the ingress of disturbing flow (B) through the coupling,and therefore reduces turbulence (C) in the interior, as seen in FIG. 4.

In a simple embodiment, the labyrinthine passage for obstructing theingress of disturbing flow (B) can be defined by fitting together aflange (7) of the centrifugal fan (3) and two flanges (8) of the suctioninlet (1), like in the embodiments of FIGS. 4 and 7, or conversely, likethe embodiment of FIG. 6; but the greater the number of flanges (7) andflanges (8) that are fit together, the more effective the obstruction ofpassage of the disturbing flow (B) through the coupling defined aroundthe opening (2), and therefore the lower the loss of performance forsuctioning the flow of fluid (A) through the suction inlet (1).

According to the foregoing, embodiments of different forms in whichflanges (7) of the centrifugal fan (3) are fitted together with flanges(8) of the suction inlet (1), such as the embodiments of FIGS. 5, 8 and9, which are only non-limiting, representative examples.

For that purpose, flanges (7) of the centrifugal fan (3) and flanges (8)of the suction inlet (1) can furthermore be fitted together in the axialdirection of suction, like the mentioned examples of FIGS. 5 to 9; butthey can also be fitted together in the radial direction, like theexamples of FIGS. 10 and 11, which are also non-limiting, the concept ofthe invention remaining unaltered as regards defining a labyrinthinepassage that obstructs the ingress of disturbing flow (B) through thecoupling defined around the opening (2) of the suction inlet (1).

To achieve a more effective closure in the sense of preventing theingress of disturbing flow (B) through the coupling between thecentrifugal fan (3) and the suction inlet (1), the inclusion of a fillerin the labyrinthine passage of the coupling with a soft moldablematerial, such as gel, silicone, etc., is envisaged, whereby achieving aclosure that prevents almost entirely the passage of air or any othergaseous fluid through the coupling. In this case, the filler materialdoes not obstruct the rotational movement of the centrifugal fan (3),because since it is a soft moldable material, when said centrifugal fan(3) rotates, it will make a channel in said filler material that allowsfree rotation with virtually no friction.

1. A coupling between a centrifugal fan and the suction inlet thereof,comprising a suction inlet defining an opening for the passage of a flowof fluid (A) and a centrifugal fan rotatably mounted with respect tosaid suction inlet for driving the flow of fluid (A), a closure couplingbeing formed around the opening, between the centrifugal fan and thesuction inlet, by means of respective concentric flanges between whichthere is play for freedom of rotation of the centrifugal fan,characterized in that the closure coupling around the opening fitstogether flanges of the centrifugal fan and flanges of the suctioninlet, which flanges define therebetween a labyrinthine passage thatobstructs the ingress of disturbing flow (B) through the coupling. 2.The coupling between a centrifugal fan and the suction inlet thereofaccording to claim 1, wherein the closure coupling around the opening isdefined by means of flanges of the centrifugal fan and flanges of thesuction inlet, fitting them together in the axial direction of suctionof the flow of fluid (A).
 3. The coupling between a centrifugal fan andthe suction inlet thereof according to claim 1, wherein the closurecoupling around the opening is defined by means of flanges of thecentrifugal fan and flanges of the suction inlet, fitting them togetherin the radial direction of suction of the flow of fluid (A).
 4. Thecoupling between a centrifugal fan and the suction inlet thereofaccording to claim 1, wherein a filler with a soft moldable material isincluded in the labyrinthine passage defining the fitting together offlanges of the centrifugal fan and flanges of the suction inlet.